[Treatment of premenstrual syndrome with Chinese medicine formula, baixiangdan capsule: implications for neuron viability and GABA(A) receptor modulation in rat cortex].

OBJECTIVE: To explore the effects of Baixiangdan capsule (BXD), a Chinese medicinal formula, on the premenstrual syndrome (PMS) rats with Liver-qi invasion and the possible underlying micro-mechanisms. METHOD: Wistar rats were randomly assigned to two groups, nomal group and BXD group After evaluated by macro-behavior observation and open-field test, MTT assay and the whole-cell patch clamp recording were performed respectively to evaluate the effects of serum from BXD capsule-treated rats on the viability and GABA(A) R-induced currents of cortical neurons in vitro. RESULT: In the open-field test, the crossing score, rearing score and total score of BXD rats decreased significantly (P < 0.05), compared by the normal rats. Compared with cells exposed to serum of normal rats, the viability values of those incubated with serum of BXD group for 24 h and 48 h significantly increased (P < 0.05), measured by MTT assay. The results of whole-cell patch clamp recording showed that concentration-response relationship curves revealed an EC50 value of (29.0 +/- 4.4) micromol x L(-1) and a Hill coefficient of 1.07 for normal-exposed cultures, (63.5 +/- 8.2) micromol x L(-1), 1.04 for BXD-exposed cultures after incubation for 24 h. Furthermore, the difference in EC50 values was statistically significant (P < 0.01), that in the Hill coefficient was not obvious. CONCLUSION: BXD capsule could significantly decrease crossing score and total score of open-field test and effectively enhance the neuron viability and GABA(A) receptor activity in rat cortex. Paeonimetabolins I and paeonol may play a significant role in treating PMS model rats with Liver-qi invasion by BXD capsule, and paeonol may target at GABA(A) receptor, especially.